1. Field of the Invention
This invention relates to a new class of heterogeneous catalyst having exceptional chemical and thermal stability, high upper reaction temperature limits and good catalytic activity for conversion of organic compounds which comprises a substrate which is modified by at least one amine functional member coordinated to a metal function, said amine functional member acting as a bridging member between said substrate and said metal function and organic compound conversion therewith.
2. Description of Prior Art
There has long been a need for effective, commercially practicable transition metal catalysts for such reactions as hydrogenation, hydroformylation, carbonylation, dimerization and others. Early catalysts developed for such purposes were homogeneous catalysts which suffered from, among other things, the expense of recovering, repurifying and recycling said catalysts. Changes in selectivity and reactivity were often brought about by varying ligands and by changes in operating conditions, such as, for example, temperature, pressure, reactant ratios, reaction rates and others. Catalyst losses were often so high that relatively inexpensive metals such as cobalt were used, even though such catalysts required severe operating conditions. Catalysts which were effective under somewhat milder conditions, such as rhodium complexes, were much more expensive (of the order of 10.sup.3 times as expensive), and, therefore, to insure low catalyst loss, created the requirement of costly recovery systems.
More recently, a number of heterogeneous catalysts have been developed (Belgium Pat. No. 721,686) which demonstrate activities and selectivities for certain reactions, such as, for example, hydroformylation. Those heterogeneous catalysts are comprised of transition metal complexes on ligands bonded to macroporous resins and show superior catalytic results in certain reactions, such as hydroformylation, when compared to their homogeneous anologues. However, the utility of said heterogeneous catalysts is limited by the relatively low chemical and thermal stability of the resin supports therein.
Another class of heterogeneous catalyst has been developed comprising complexed transition metals on phosphine ligands bonded to inorganic oxide surfaces (Dutch Pat. No. 7,018,453 and British Pat. No. 1,275,733). This class of catalysts has been shown to be useful in the hydroformylation reaction (Dutch Pat. No. 7,018,322).
The instant invention of a new class of heterogeneous catalysts, which catalysts comprise a substrate having a minimum surface area of about 10 m.sup.2 /g and having pores with a minimum pore diameter of about 5 Angstrom Units, said substrate being modified by at least one amine functional member coordinated to a metal function, said amine functional member acting as a bridging member between said substrate and said metal function, are demonstrated to have chemical and thermal stability unmatched by prior resin-bound heterogeneous catalysts or oxide-bound phosphine functionalized heterogeneous catalysts. Further, the catalyst of this invention has enhanced organic compound conversion activity, e.g. olefin isomerization activity, relative to other oxide-bound or resin-bound complexes. Still further, and with respect to catalytic activity, the present catalyst shows dual-functional catalytic activity, e.g. in which an olefin is hydroformylated to an aldehyde which is then converted by an acid functionality of the catalyst to an acetal in the presence of an alcohol.